The present invention relates to a fault evaluating system and, more particularly, to a fault evaluating system for four switching packages which are mutually duplexed in both the transmission and reception directions and bridge-connected to oppose each other.
In a transmission apparatus, a conventional fault evaluating system for four packages A, B, C, and D which are duplexed in both the transmission and reception directions such that the duplexed opposing packages are connected to intersect each other has an arrangement in which fault detection units A-3, B-3, C-3, and D-3 are connected to the monitor points of the switching packages A, B, C, and D, respectively, as shown in FIG. 3. The monitor results are collected to a package E which mainly performs alarm processing. A fault package is specified by the firmware in an alarm processing unit E-1 on the basis of the monitor results at the respective monitor points.
In the above-described conventional fault evaluating system, fault information from the respective monitor points of the switching packages A, B, C, and D are temporarily collected to the package E for performing alarm processing. Thereafter, a fault package is evaluated on the basis of the fault evaluating logic of the firmware in the package E. This increases the burden of the firmware. Additionally, since the firmware is interposed, the fault evaluating operation depends upon the operation period of the firmware. As a result, a long time is required from fault detection by hardware to fault evaluation. Therefore, when a fault is detected, relief processing for a main signal, which is performed by redundant system switching by selection units A-5, B-5, C-5, and D-5 on the basis of control of the alarm processing unit E-1, is undesirably delayed.